The direct exposure of soils to methanol spills results in immediate damage of surface vegetation. The miscibility, volatility, and degrad­ability of alcohols reduce the alcohol residence time in soil and mini­mizes the environmental impact. Fungal and bacterial populations, which are important agents of nutrient cycling, exhibit 80—90% recovery with 3 weeks of exposure. Total recovery of the site occurs within a period of weeks or months. In comparison, recovery of biodegradation by crude oil and petroleum products takes months or years.

7.10.2 Occupational health impacts

Occupational heath risks associated with using alcohol fuels are lower than those associated with conventional fuels. The relative toxicity of alcohol fuels depends on the means of exposure, inhalation, and inges­tion. Gasoline poses a greater occupational health risk than either methanol or ethanol as carcinogens in gasoline can be readily absorbed by the skin or inhaled.

7.10.3 Occupational safety impacts

Two major safety hazards of all fuels are fire and explosion, which can occur because of improper fuel storage, spills, or vehicle accidents. The properties of alcohols and gasoline that pertain to fire and explosion risks include the flash point, auto-ignition temperature, flammability limits, and saturated vapor concentrations. While ethanol and methanol have broader flammability limits than gasoline, gasoline poses a greater risk of fire in open air. Because of the low flash point and auto-ignition temperature of gasoline, gasoline is more likely to ignite and burn rap­idly; therefore, the fire hazard is greater for gasoline.

Alcohol-fueled fire can be more readily contained than a gasoline-fueled fire of equivalent volume because alcohols have a lower heat of combustion than gasoline and less of the energy released is converted to radiant heat. Therefore, energy release and potential damage from an explosion caused by alcohol would be less than that of an explosion caused by gasoline.